U.S. Pat. No. 3,146,169 pertains to the formation of an inert coating which surrounds an active agent to be dispensed from a tablet. A hole is mechanically punched in the inert coating for release of the active agent.
U.S. Pat. No. 4,271,113 shows the production of an osmotic device, which includes an exit passageway in a semipermeable coating, by pressing a depression into the core member, at least a portion of which remains as a hole in the coating after the semipermeable coating is sprayed onto the core. U.S. Pat. No. 3,916,899 generally suggests the use of drilling, punching, laser drilling, or casting methods to produce a passageway in an osmotic device.
U.S. Pat. No. 4,302,412 shows a method for compacting powder material into a pressed article. U.S. Pat. No. 4,601,866 shows a method for compacting powder material into a pressed article at controlled temperatures.
U.S. Pat. No. 4,088,864 shows the use of a laser to produce passageways in an osmotic device.
Although the devices of the prior art can be used to form holes in tablets and dispensing devices, it would be desirable to operate at higher production rates than presently obtained. Also laser drills are quite expensive compared to mechanical punches, and their speed is limited by the cycle time of the laser. When prior art mechanical punches were operated at high speeds the tablets tended to hang up on the punch point.
It is therefore an object of the present invention to provide a method and apparatus for producing a passageway in a dispensing device, such as an osmotic dosage form, which is inexpensive and capable of operating at high speeds.
It is another object of the invention to provide a passageway-producing method which is useful for tablets having round, oval, oblong, or other shapes.
It is yet another object of the invention to provide a method of producing an osmotic device having a pierced compression coating.
It is another object of the invention to provide a pressure-actuated piercing mechanism for producing a pierced dispensing device.
It is yet another object of the invention to provide a piercing means which retracts the piercing point from the interior of the pierced object, and thus frees the object from the piercing means.
These and other objects of the invention will be apparent to one skilled in the art in view of the disclosure and claims herein.